Electrical precipitation apparatus



Feb. 20, 1945. wHlTE I ELECTRICAL PRECIPITATION APPARATUS' Filed July 15 3 Sheets-Sheet IN VEN TOR. Heeey UT WMTE,

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` A Trae/vsn Feb. 20, 1945. H. J. WHITE ELECTRICAL PRECIPITATION APPARATUS Filed July 15. 1942 5 sheets-sheet 2 INVENToR. Maerz-J.' Wil/T5,

ATTO/@wen Feb. zo, 1945. H J, WHWE 2,369,877

ELECTRICAL `PREC IPITATION APPARATUS Filed July 13, 1942 3 Sheets-Sheet 3 INVENTOR. ,Ef/#eey di PVA/ITE,

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Patented Feb. 20, 1945 2,369,877 ELECTRICAL PRECIPITATION APPARATUS nmy J. White, cambridge, Mass., assigner to Research Corporation, New York.l N. Y., a corporation of New York Application July 1s, 1942, semi No. 450,711

5 claims. (o1. isa-7) The present invention relates generally to apparatus for electrical precipitation of suspended particles from gases', and moreI particularly to multiple stage precipitators of the type in which the particle-laden gas passes alternately through electrostatic charging fields, in which corona discharge is maintained to charge the suspended particles, and spatially separate electrostatic precipitating fields, of high stress but substantially free from corona discharge, in which the charged particles are precipitated. There may be one or more charging fields, and there will normally be a precipitating field following each charging field. The gas is thus subjected successively to two kinds of functionally distinct fields, and for this reason a precipitator of this type may be termed a multip le stage precipitator. In itselemental form, such a precipitator has each of its charging fields established between two electrodes, of which one is a discharge electrode and the other is a nondischarging electrode, and has each of its precipitating fields established between two substantially non-discharging electrodes.` A multiple stage treater of this general type was disclosed in Patent No. 1,343,285, granted June 15, 1920, to W. A. Schmidt, and the advantages of a precipitator employing a spatially separate precipitating field,v

as well as the advantages of a multiplicity of sets of alternating spatially separate charging and precipitating electrodes, are set forth therein. Reference is also made to Patent No. 2,199,390,

granted May 7, 1940, to E. Anderson, in which the advantages of a precipitating field that is spatially separate from the charging lfield are set forth in some-detail. i 1

In the following description and appended claims, the term discharge electrode will be understood to designate an electrode that facilitates corona discharge, because it has a conguration that establishes a sufliciently high potential gradient at or near its surface to create corona ,discharge before there is a disruptive discharge or sparkover. For this purpose, the discharge electrode usually takes the form of a member' of small surface area. such as a small diameter wire Ybca'usesithas-arconfiguration that -establishes a sufficiently lowiield concentration ator near the surface to suppress corona discharge at elevated potentials lower than the voltage required for disruptive discharge or sparkover. For this purpose, a non-discharging electrode is usually one of extended surface area, substantially free from sharp corners or other parts of sharp surface curvature vat all portions which are located Within the electric field, so as substantially to avoid ionization or corona discharge at that electrode.

The present invention deals with improvements in the construction -of multiple stage electrical precipitators of the general type referred to, and, in certain particular aspects, may be regarded as having to do especially with improvements in the vprecipitatior shown in'Figs. 5, 6 and 7 of Patent No. 2,275,001, granted March 3, 1942, to E. Anderson. The precipitator disclosed in said patent has collecting electrodes of the so-called pocket type, i. e., forming collecting pockets outside but immediately adjacent the main gas stream, but

while the present invention is particularly applicable to precipitators having such pocket electrodes, and is here shown in that association, it is nevertheless to be understood that the present preferred use of collecting electrodes of the pocket type implies no necessary limitation thereto.

yThe prior precipitator referred to involves a twostage electrode construction in which the charging and precipitating stages constitute two entirely separate structures, the charging stage embodying an assembly consisting of a plurality of non-discharging electrodes, as-vertica1 cylinders, opposed by discharging electrodes, such ,asflne wires, together with asuspension structure, while the precipitating stage embodies an assembly consisting of a plurality of non-discharging electrodes in the` form of vertical curtainsextending longitudinally ofthe gas stream vand spaced trans-l versely thereof, opposed by longitudinally extending series of pocket type collecting electrodes, all mounted on supporting structure which is entirely separate of the structure making up the first or charging stage.

A general object of the present invention isthe provision of simplied and improved electrical precipitation apparatus of the-class mentioned in the foregoing, discussion.v

A further and more particular object is the provision, in electrical precipitation apparatus of the multiple stage variety, of a simple and improved unitary suspension system for both the discharging electrodes of the charging fields and the nondischarglng electrodes at one side of the precipitating fields.

A still furtherobject is the provision of an electrode vsuspension system adapted for interchange-` 'lecting electrodes.

able support of electrode elements of both the discharging and non-discharging types. arranged in a row or rows extending longitudinally of the gas stream, whereby electrode elements of both such types may be supported thereon in any order dic tated by local requirements.

In the construction provided by the present invention, and considering nrst a horizontal gas ilow type of precipitator, the non-discharging high-tension electrode at one side of each precipitating fleld is of the rod curtain type. comprising a row of vertical rods extending longitudinally of the gas stream, being removably received within and positioned by suitable holes formed, preferably 4at equal spacing, in two vertically spaced and aligned rails. Heads on the `upper ends of the rods engage the upper 'of these rails to provide vertical support for the rods.

The non-discharging electrode at the other side of the field comprises an electrode structure,

preferably ofthe pocket type. spaced transversely of the precipitator from the rod curtain and extending parallel thereto, so that a gas duct is formed between the two electrodes, and the electrical iield extends transversely across the gas duct. Wherever along the length of the gas duct it may be desired to have a transversecharging eld, one or more of the rods of the-high tension rod curtain are removed from the rails, and substituted for by a vertical discharging electrode, which may be a ilne wire, twisted square bar, twisted ribbon, or the like, such discharging electrode being provided with suitable adapter means may be found most eifective for local conditions; and, from a structural standpoint. there is gained the advantage of a single, simple unitaryy supporting structure for the high-tension electrode elements of both the charging and precipitating nelds. The invention may also be-incorporated .in a vertical gas flow type of precipitator. as will later be set forth in more detail. v

A horizontal gas ilow electrical precipitator of the class mentioned above ordinarily has a hopper-shaped bottom adapted to receive collected l vparticles falling from the collecting electrodes.

In order to minimize gas flow through this hopper-shaped bottom, and consequent re-dlspersion of collected dust, transverse baffles have been used therein. With such a partitioned construction, there are still some vgas currents in the several compartmentsof the hopper-shaped bottom, and these gas currents are found to be laden with a certain amount of re-dispersed dust. 'I'his .re-dlspe dust carries some electrical charge and hence will tend somewhat to precipitate out, but its charge and therefore its tend- `encyto precipitate are very much less than immediately after passage through a corona discharge,

A further object of the invention is, accordinsly, the provision ofmeans for substantially increasing the tendency of thel re-dispersed dust pension means above. The particle-laden gas currents circulating within the compartments of the hopper-shaped bottom tend to rise along these transverse bailies, and are thus -delivered directly to the corona discharge occurring about the discharge electrodes which are positioned immediately' over the baiiles. Thus a. large proportion of the re-dispersed dust is strongly recharged, and its tendency to .precipitate on the collecting electrodesgreatly enhanced.

Various additional objects and accomplishments of the invention will appear and be described inthe course of the following detailed description of one present illustrative embodiment thereof, reference for this purpose being had to the accompanying drawings, in which:

Fig. 1 is a longitudinal vertical section of a preferred and illustrative horizontal gas flow precipltator constructed in accordance with the invention, being a view taken as indicated by broken' line lJ-I of Fig. 2; Fig. la is an enlarged detail taken from Fig. l; Fig. 2 is a plan section taken on vbroken line 2-2 of Fig. 1; Fig. 3 is a vertical transverse section taken on broken line 3-,3 of Fig. 1; Fig. 4 is a detail vtaken on line 4-4 of Fig. l; Fig. 5 is a detail section taken on line 5--5 of Fig. 4; Fig. 6 is a detail section taken on lin-e 6-6 of Fig. 1; Fig. 7 is a detail section taken on line 1-1 of Fig. 2; Fig. 8 is a detail section taken on line 8-8 of Fig. 7; Fig. 9 is a detail section taken on line 9-,9 of Fig. l; and Fig. 10 shows an illustrative discharging and non-discharging electrode structure in accordance with the invention for a vertical gas iiow type of precipitator.

The preclpitator of Figs. 1 9 ls provided with a generally rectangular shell or housing I0 derining a horizontal gas passage between an inlet Il at one end and an outlet i2 at the other. This housing I0, in the embodiment of the invention here chosen for illustration, includes vertical sides I3, a hopper-shaped bottom Il, preferably equipped at the bottom with a screw conveyor discharge means l5 for the collected dust, and

a top comprising end sections l1 and a removable central section or panel I8 adapted to be' removed to permit access to be gained to the interior ofthe precipitator. Av pair of longitudi-` nally-spaced transverse members I9 and 20 at each end of the housing supports the correspond-y ing top end section I1, andl the removable central panel I8 of the housing top rests at opposite ends on the members 20 and abuts top end secltions I1, in the manner clearly illustrated in Fig.

1. The endsof the transverse members 2li are shown in Fig. 3 to be supported from side walls |3 by means of brackets 20a, and the transverse members I9 may be similarly supported.

The transverse members 20 may be described generally as of channel cross-section, having web 22, side anges 23 andV 24, and a flange portion 25 turned inwardly from flange'24. The two carried bythe gas Icurrents in the partitioned hopper-shaped bottom to precipitate on the coliles in the hopper-shaped bottom with the dis.

charge electrodes carried by the electrode susmembers 2li are arranged with their ilanges 2l' uppermost, and with their'channels facing one another, as-shown in Fig. l. The members I8 may be of similar cross-section, and arranged as in Fig. l.

Engaging and welded to the under sides or ilanges 423 of the channel members 20, near the two ends of the latter, are the upper ,ends of vertical members 26, preferably of U-shaped cross-section. I'he lower` ends oi these U-shaped members 26 engage and are -welded to transverse channel-shaped members 2'8, of cross-section .similar to members .20. extending across the housing at the dividing plane between the rectangular vportion of the housing and the hopper-shaped bottom I4. These members 28 are oriented with their channels facing one another, the anges 29 collecting electrodes 35 extending `longitudinally and spaced transversely of the housing, each comprisinga series or row of V-shapedelectrode elements 3-6which are aligned and spacedl from one another in -the direction of gas flow, as may be seen. best in Fig. 2. Sharp edges are removed from the open ends of each V-shaped element by turning the vertical edge portions 31 back, as illustrated in Fig. 5. The upper end portions of the series of V-shaped elements 36 of each collecting electrode are received within V-shaped slots 38 formed in the web 39 of a longitudinal channelshaped member 46 (Fig. 4) whose ends extend into the channels of the members 26. and rest on and are supported by the lower flange portions 23 thereof. The V-shaped members `36 are hung from members 40 in any suitable manner; for instance, as indicated in Fig. 5, their upper corner portions 42 may be turned over so as to engage the web of the member `40. Members -46 are transversely spaced at desired intervals on they members 20; for instance, rivets -43 set into.and

projecting upwardly from the vlower flanges 23v of the members 20 may be engaged with holesv 44 in the webs of the Imembers 40.-

The two outside rows or series of V-shaped electrode elements 36 are preferably positioned at relatively close spacing tothe side walls I3 of the shell. To close'off gas circulation through any space that may be left, vertical baille strips 45 may bemounted at suitable intervals therein (see Fig.2).

Preferably, though vnot constituting a part of the present invention, baille members 41 are employed between the lower portions of the several transversely-spaced series of collecting electrodes 35, at the level of the top side of the hoppershaped bottom I4. These baille members 41 extend longitudinally of the collecting electrodes between the two lower transverse 'members 28, being received at their ends within the channels of said members 28 an'd supported by the flange portions 38 thereof, as clearly illustrated in Figs.

1 and 6. In the form illustrated, these bafiles have portions 48 sloping downwardly and away from the edges of the V-shaped electrode elements 36,

and are formed at the bottom of portions |48 with inwardly turnedlflanges 49 resting at the' ends on flange portions 30 of vtransverse members 28, and at the top with inwardly turned flange portions 50 notched suitably to receive the edge portions of the electrode elements 36. The ends of the baille members 41 engage and are welded to the webs I5I of members 28. It will be evident that these bailles serve to space. the lower end porcharged into the hopper-shaped bottom I4, the

incline of the w-alls 48 being sufcient to prevent fined by the several series or rows of collecting electrodes 36. the latter being spaced properly (see Fig. 2) to accommodate these rows of discharging and non-discharging electrodes with proper transverse. spacing for the necessary elec- 'trical action. The supporting structure for these high-tension electrodes includes a frame at each end of the housing, spaced somewhat beyond the ends of the rows of collecting electrodes 36, and hung from suitable suspension insulators '6I mounted vin tubular housings 62 extending through and supported by the top sections I1 of the enclosing housing of the precipitator. There are four of these suspension insulators 6 I, two for each frame 66. Each insulator has a central vertical supporting rod 63 extending therethrough and on downwardly through the upper horizontal transverse member 64 of the frame 60. These members 6-4 are preferably of the same channel cross-section as the member 20. being arranged with their channel sides facing awayr from the electrode structures, and oriented as clearly il- .lustrated in Fig. 1. Thus, the high-tension supvertical end members `61, preferably aligned with rows of pocket collecting electrodes 36 (see Fig.

3), so as not to interfere with the gas passages between the rows of electrodes 36, the upper ends of the members 61 engaging and being welded to the lower ilanges of the members 64, and the frames KIiIl also include a lower transverse member 68 welded to the lower ends of vertical members 61, members 68 being preferably of th'esame cross-section asthe members '614, and also disposed with their channel sides facing awayfrom the electrode structures.

Connected to electrode rod 63, at the upper end.

of one o'f the insulators 6I, is a conductor 68,

which passes through insulator 69a in the side of bushing housing 6.2, and connects on the outside to electrical conductor 69h, which will be understood to be energized from one terminal, usually the negative terminal, of a suitable high-tension source of uni-directional current. The precipitator housing, and therefore the pocket collecting electrode structure, is electrically grounded, as is the positive terminal o f the source of current.

The upper and lower transverse members 64 and 68 of the two high-.tension frames 6I) support parallel upper and lower longitudinally-extending rails 10, spaced uniformly between the 4rows of collecting electrodes 36, and adapted for support of the presently described high-tension disch-arging and non-discharging electrodes. These rails are generally of inverted U-shape in cross section, with inwardly turned flange portions 1l at the edgesof the two sides 12. They are supported at their ends on the upper ends of pins 13,

which projectupwardly from the cross members 64 and I68 of high-tension frames 60. As here shown, these pins 13 pass through suitable holes in the upper flanges of members 64 and 68 and rest -at their lower ends on the lower flanges of said members (Fig. l). The pins 13 pass between the flange portions 1I'of rails 10 and engage the under sides of their U-tops, as will be understood from an inspection of Fig. 1. The U-tops of the upper and lower rails 10 are provided with uniformly and relatively closely spaced pairs of vertically-aligned holes 15 adapted to receive with free sliding t vertically-disposed non-discharging electrode rods 16 and discharging electrode members 11. The former may be solid rods or tubes, though it is preferred, for simplicity and inexpensiveness of construction, to employ seamed tubing. 'I'he non-discharging electrode rods 16 will, oi course, be understood to be of suiilcient diameter that high electrostatic field stresses at their surfaces, such as might cause ionization of the surrounding gases, will be avoided. The upper ends of the electrode rods 1'6 are furnished with heads 18 adapted to engage the U-shaped tops oi upper; rails 10 for the purpose of support of the rods. These heads 18 are conveniently provided by the simple expedient of welding rivets 19 in the upper ends of members 16.

The discharging electrode members 11 include portions having formations o'f relatively small radius of curvature, such as will establish high electrostatic stress,-suiiicient to cause ionization of the surrounding gases. Suitable known forms include fine wires, twisted square bars, twisted about one-third the length of the electrode structure and the other about two-thirds the length thereof. As before, one or two rod-receiving holes 15 are left unoccupied between the additional rows of discharging electrodes 11 and the next adjacent rows of non-discharging electrodes 16, in order to avoid electrical shielding of the discharging electrodes.

The discharging and non-discharging electrodes 16 and 11, being mounted on the rails 1i] connected -to the high-tension frames 60 supported directly from the conductor rods 63 of the high-tension insulator bushings 5I, are maintained at a high direct-current potential, usually of negative sign. The housing structure I0, and therefore the pocket-type V-shaped electrodes 36, are electrically grounded, as previously stated. It will be understood that an electrostatic fleld will be established between each electrode member mountedl on the rails 10 and the adjacent V- y shaped collecting'electrodes 38, and that this eld ribbons, and the like. The vpreferred form herechosen for illustrative purposes embodies a twisted ribbon 80. As here illustratively shown, the upper end of the twisted ribbon is inserted and Welded within a slot 82 cut in the lower end of rivet 83, which is removably mounted in a selected hole 15 of upper rail 10, the head B4 of the rivet engaging the top of the rail, as illustrated. A short cylinder l85 is incorporated in the ribbon where the latter passes through the lower rail 10 (see Fig. 9). the lower rail 10 and its ends inserted and welded within slots 86 cut in the ends of the cylinder 85. The cylinder 85 thus serves as a filler or spacer element being received with sliding t within'the hole 15 of the rail, and serving to center and support the electrode with respect to the lower rail 10.

As will be evident from Fig. 2the first electrode-receiving holes in the rails 1li are located in transverse alignment with the rst transverse row of ift-shaped pocket collecting electrode elements 36, and are continued at uniform, relatively close spacing to the last transverse row o'f V- shaped electrode elements. In the rst transverse i'structures,` additional transverse rows of discharging electrodes may be inserted. As here shown,

two such additional rows' are illustrated, onewill be of very high intensity at the sharp edge formations of the `discharging electrode 11, suiiicient to cause ionization of the surrounding gases, while being of insuilicient intensity at the surfaces of the non-discharging electrodes 16 to cause gas ionization. Thus, the vdust-laden gas, passing first between the discharging electrodes 11 and the first V-shaped electrodes 36, jis ionized, causing the dust particles to become electrically charged so as to migrate toward'the positively charged collecting electrode structhre. Passing beyond the charging iield, the charged dust particles come within the influence of the precipitating eld between the rods 16 and the V-shaped pocket electrodes 36, and continue their migration toward the latter and into the spaces between them, iinally todeposit on eir surfaces.

The dust particles thus received within the |pockets" between adjacent V-shaped electrode elements 35 are removed from the gas currents into relatively quiescent zones, and the tendency As shown, the ribbon is broken at' row of electrode-receiving holes 15 `are placed a for re-dispersion of Aparticles deposited on the electrode elements 36 due to erosion by the gas stream is minimized. The gas then passes through a second charging or ionizing field at the transverse plane defined by the second transverse row of discharging electrodes 11, whereby the dust still carried by the gas is re-charged, and precipitation on the following collecting electrode elements 36 under the influence of the next following precipitating field is substantially enhanced. Finally, the gas passes through a third ionizing held provided by the third transverse row of discharge electrodes 11, and then through a third precipitating eld, and the process thus repeated. Of course, as many such transverse rows of discharging electrodes may be incorporated as desired, depending largelyupon local requirements, though more than 4two such rows in addition to the first will usually fail to increase the dust recovery to any substantial extent. The construction described permits adjustment of the transverse krows of discharging electrodes `11 in directions longitudinally of the gas passages. and permits them tobe readily placed atwhatever location may yield best recovery for any given field installation. As will be quite evident, it is a very simple matter to adjust the number or the longitudinal' positions of these additional transverse rows of discharging electrodes, it being only necessary to lift the removable housing-cover Il, and to place the discharging electrods ln any desired holes of the' supporting rails 1I, several-or the 'non-discharging electrode rods 'I6 being removed or replaced to accommodate the new position of the discharging electrodes. The construction described provides the dual advantage of, rst, a simple, unitary mechanical supporting assembly for both the discharging and the non-discharging hightension electrodes, and, second, a construction permitting adjustment of the number and positions of the discharging electrodes practically at will.

The dust particles gatheredon the surfaces of the V-shaped collecting electrodes 36 fall from time to time, aided preferably by intermittent operation of a suitable rapping mechanism, not illustrated herein, the dust descending between the outside surfaces of the sloping portions 48 of adjacent bafes 41, and also between the edges of the flange portions 50 of the baffles. to be received by the hopper-shaped bottom I4. To

prevent substantial circulation of gas longitudinally of the hopper-shaped bottom I4, such as would otherwise tend very substantially to redisperse the dust collected therewithin, transverse vertically-disposed baille plates 90, 9| and 92 are mounted therein. There is, however, some turbulence within the several compartments dened by these bailles, and despite the provision of 'the bailles 41 at the top of the hopper, there is some resulting iiow of gas from the compartments back upwardly between the bailles 41 and into the spaces between the electrode elements above. It is a feature of the invention that the baffles 90, A9| and 92 are mounted in the same vertical transverse planes withl the transverse rows of discharging electrodes 11, so that the gas so owing upwardly from the hopper will be guided by the baffles to pass largely through the ionizarranged longitudinal members |0I, a top horizontal member |02 connecting the upper ends of longitudinal members IOI, and a bottom horizontal member |03 connecting the lower ends thereof. 'I'he lower portions I 04 of longitudinal frame members |0I are shown as\inclined inwardly and downwardly, so as to conform to the collecting electrodes of the precipitator of the aforesaid Rder patent, though such formation is', of course, not essential. The members |0I, |02 and |03 of frame |00 are here exemplified in the form of pipes welded together at their junctures, though this is merely illustrative and in no way limitative on the invention. y Further, the frame |00 is here indicated as suspended by. means of hangers |05, which will be understood as hung from any suitable supporting structure above, as, for instance, that shown in the Rder patent. It is to be understood that one such frame as here indicated at |00 may be placed in each of` the parallel vertical gas du'cts of a multiple electrode precipitator such as shown in the aforesaid Bilder patent, and in such case the several frames |00 may be inter-connected and spaced by any suitable spacing means. A fragmentary portion of such spacing means is indicated at |06 in Fig. 10. l

The two members |0I of frame |00 are formed with longitudinally-spaced pairs of aligned holes |01 for removable reception of horizontally-disposed discharging and non-discharging electrode elements. The discharging electrode elements,

. here designated by numeral |08, may be any suiting elds established lby the discharging electrodes. Any re-dispersed dust carried by this upowing gas is accordingly passed, to a large extent, through these ionizing fields and is therefore immediately strongly re-charged,'giving vit an immediate tendency to re-precipitate. In order to permit placement of the bafiles 9| Vand 92 in the transverse planes in which the second and third transverse rows of discharging electrodes are finally located, the baflles 9| and 92 yare here illustratively shown as provided with lugs 93 adapted to be secured to the side walls of the hopper by means of bolts 94, which may be sol insorted as to accommodate the positions of the I baffles to the planes of the discharging electrodes.

Sinne the first row of discharging electrodes 11 is located in a permanently fixed plane, the rst baille may be permanently installed in `that same plane, as by being welded to the walls of the hopper. A door such as may be'provided able members having sharp formations or forma- Y tions of relatively small radius of curvature, and

.receive nuts engageable with the member |0I.-A

' in a side wall of the hopper to permit installation larlv for use in agnrecipitator of the type shown inPat. -No. .1.882.949 to Rder, issued October 18, 1932. and reference may be had to that patent for an illustrative showing of a suitable vertical l:zas flow type of precipitatorfthough the invenfion is. of course, not necessarily limited to the spfcie type there shown.

In Fig. T10, numeral |00 designates generally a and nuts II3 screwed on the other end for engagement with the two members |0| of the supporting frame. The nuts III and 3 are desirable to prevent longitudinal displacement of the electrode elements, such as would otherwise be likely to occur with the electrodes in the horizontal position.

In the specific arrangement here shown, the rst or bottom holes |01 of the frame |00 are occupied by a discharging electrode |08, and there are two additional discharging electrodes |08 at positions approximately one-third and two-thirds of the height of the frame. The remaining holes 001, except for one or two holes -on each side of each discharging electrode |08, are occupied by non-discharging electrode rods |09. The electrode elements |08 and |09 lare removably received in the holes |01 and, as with the horizontal gas flow type of precipitator heretofore described, `their positions may be changed at will, depending upon local requirements. In the horizontal ,out of position. This is prevented by providing The electrode supporting structure of Fig. 10 has been particularly described as adapted for use in a vertical gas ilow type of precipitator' as shown in prior Patent No. 1,882,949 to Bilder, though by suitable modification, it may be employed in many other types of vertical gas ilow precipitator; for, instance, it may lie-substituted for the high-tension electrode system shown in Figs. 1 and 2 of Patent No. 1,926,025 to E. Anderson, or for the high-tension electrode systems of the multiple section precipitator disclosed in Patent No. 2,061,045 to Riider. or in others.

It will be understood that the drawings and description are merely illustrative of, rather than restrictive on, the invention, and that various changes in design, structure and arrangement may be made without departing from the spirit and scope of the invention or or the appended claims.

I claim:

1. Electrical precipitation apparatus for removing suspended particles from a gas, comprising a shell enclosing a horizontal passageway for a stream of the gas and provided with a hoppershaped bottom below said passageway, an electrode system in 'said' passageway comprising grounded collecting electrode structure extending longitudinally thereof and high-tension charging and precipitating electrode structure extending longitudinally thereof in parallelism and at transverse spacing from said collecting electrode structure, said charging and precipitating electrode structure including vertically disposed discharging electrodes spaced longitudinally o! said gas passage and creating with said collecting electrode structure charging ilelds extending transversely of the gas passageway in longitudinally-spaced vertical planes, and bailleplates within and extending transversely across said hopper-shaped bottom and substantially aligned with the planes of said charging ilelds.

2. Electrical precipitation apparatus for removing suspended particles from a gas, comprising a shell enclosing 'a horizontal passageway for a stream of the gas and provided with a hoppershaped bottom below said passageway, an elechopper-shaped bottom and substantially aligned with the planes of said charging fields.

'3. Electrical precipitation apparatus for removing dust particles from a stream o! gas, comprising ailrst electrode system which includes transversely-spaced complementary non-discharging and discharge electrodes, a second electrode system which includes transversely-spaced complementary non-discharging electrodes, the transversely-spaced electrodes of said rst and second systems being arranged to deilne a longitudinallyextending gas passage open at both ends and extending betweenthe electrodes of said ilrst and second systems in succession,v the non-discharging electrode of saidilrst system being a pockettype collecting electrode having lateral boundaries spaced apart a substantial distance, said collecting electrode having surfaces for electrical precipitation of suspended particles and having portions that detlne and shield from the gas stream one or more particle-collecting zones between said lateral boundaries, and means for impressing a high potential' across the complementary electrodes of each system.

trode system in said passageway comprising grounded collecting electrode structure extending longitudinally thereof and high-tension charging and precipitating electrode structure extending longitudinally thereof in parallelism with and at transverse spacing from said collecting electrode structure, said charging and precipitating electrode structure including a substantially horizontal rail having a plurality of vertical electrode receiving holes spaced along the length thereof, a plurality of .vertically-extended discharging electrode elements supported .in selected substantially longitudinally-spaced holes 'of said rail, vertical non-discharging electrode elements sup-V ported in other holes of said rail, said discharging electrode elements creating with said collecting electrode structure charging fields -extending transversely of the gas passageway in longitudinally spaced vertical planes. and baille plates within and extending transversely acrosssaid vlcs 4. Electrical-precipitation apparatus for removing dust particles from a streamfjgas, comprising a first electrode system which includes transversely-spa'ced complementary non-discharging and discharge electrodes, a second electrode system which includes transversely-spaced complementary non-discharging electrodes, the transversely-spaced electrodes of said first and second systems being arranged to dene a longitudinallyextending gas passage open-at both ends and extending between the electrodes of said first and second systems in succession, the non-discharging electrode of said first system aud one of the nondischarging electrodes of said second system being pocket-type collecting electrodes eachhaving lateral boundaries spaced apart a substantial distance, said pocket-type collecting electrodes each having-surfaces for electrical precipitation of suspended particles and having portions that define and shield from the gas stream one or more particle-collecting zones between said lateral boundariesand means for impressing a high potential across the complementary electrodes of each system. v

`5. Electrical precipitation apparatus for removing suspended particles from a stream of gas, comprising a longitudinally-extending non-discharging collecting electrode structure dening one side of a longitudinal gas duct, and high-tension discharge and non-discharging electrodes positioned in succession in opposition to said collecting electrode structure and defining the other side of said gas duct, said collecting electrode structure being a pocket-type collecting electrode having lateral boundaries spaced apart 'a substantial distance, .said collecting electrode having surfaces for electrical precipitation of suspended particles and having portions that detlne and shield from the gas stream'a plurality o! particlecollecting zones between said lateral boundaries.

HARRY J. WHITE. 

